If you decide to take them apart, do all of the refurb, new bolts if necessary, new gasket, etc. But I always take them and have them surfaced at the machine shop after messing with them. To surface them, they need to be together with gasket in place, torqued together properly, then they are surfaced as one. I paid $50 to have that done recently. It just ensures you won't have any leaks afterwards. This of course in addition to fixing the heat riser properly.
